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Biomedical subjects

B T Nguyen

Publications and source records attributed to B T Nguyen.

42 records · Page 3Linked to original sources
PubMed1976

Spontaneous interaction in vitro between lymphocytes and syngeneic peritoneal macrophages of mice.

Ficoll-purified lymphocytes (peritoneal, splenic, or thymic) and macrophages (peritoneal) from Toxoplasma-immune and normal female NMRI mice were used. Suspensions of washed cells were made in medium 199 containing 20% heat-inactivated normal calf serum. Sixty minutes after the adherence of 10(5) macrophages to cover slips in Leighton tubes, lymphocytes were added in various concentrations. The mixed cellular population was then incubated at 37 C. Eighteen hours later, most of the lymphocytes were firmly attached to macrophages to form rosettes. This cellular interaction, which was temperature, cell ratio, and time dependent, occurred in the absence of any particular antigenic stimulation. Morever, the reaction was cytotoxic only for adhered lymphocytes as judged by staining with 0.2% trypan blue. Splenic and thymic lymphocytes were bound in significantly greater number than peritoneal lymphocytes. Incubation of macrophages for more than 48 h at 37 C before the addition of fresh lymphocytes markedly reduced rosette formation. Treatment of macrophages and lymphocytes with mouse anti-immunoglobulin did not affect the reaction. The labeling of lymphocytes with fluorescent anti-mouse sera and the use of nude NMRI mice showed that both B and T cells can form spontaneous rosettes with syngeneic peritoneal macrophages.

Animals↗
PubMed1976

[Search for blast cells in the blood following transplantation (author's transl)].

The appearance of transformed lymphocytes in the circulating blood of transplanted patients may easily be followed by examination of blood smears. There is a significant relationship between the number of peripheral lymphoblasts and the course of the graft. The reliability and specificity of the test are discussed.

Graft Rejection↗
PubMed1975

In vitro activity of cotrimoxazole on the intracellular multiplication of Toxoplasma gondii.

Cotrimoxazole, from 60 mug/ml, inhibited the replication of Toxoplasma gondii within Hela cells and mouse peritoneal macrophages. The percentage of inhibition reached practically 100% after 18 hours of treatment at 37 degrees C. More prolonged treatment resulted in an eradication of the organisms from the cell monolayers. In contrast, similar doses of spiramycin were quite ineffective against intracellular toxoplasma. The active doses of cotrimoxazole used were not harmful for cell cultures. Cotrimoxazole also destroyed clones (rosaces) of toxoplasma which were formed during the past 18 hours of intracellular replication in the absence of the drug. Trimethoprim was the only effective compound of cotrimoxazole on intracellular parasites; the adjunction of sulfamethoxazole produced a marked synergistic effect. The present findings confirm the great efficiency of cotrimoxazole in the treatment of experimental toxoplasmosis in mice performed previously in this laboratory.

Animals↗
PubMedDate not supplied

Rationale for the combination of cryoablation with surgical resection of hepatic tumors.

Only 5% to 10% of metastatic and primary liver tumors are amenable to surgical resection. Hepatic cryoablation has increased the number of patients who are suitable for curative treatment. The aim of this study was to evaluate survival and intrahepatic recurrence in patients treated with cryoablation and resection. From June 1994 to July 1999, thirty-eight surgically unresectable patients underwent a total of 42 cryoablative procedures for 65 malignant hepatic lesions. Twenty patients underwent cryoablation alone, and 18 patients were treated with a combination of resection and cryoablation, with a minimum of 18 months' follow-up. The 38 patients had the following malignancies: primary hepatocellular carcinoma (n = 8) and metastases from colorectal cancer (n = 21), neuroendocrine tumors (n = 3), ovarian cancer (n = 3), leiomyosarcoma (n = 1), testicular cancer (n = 1), and endometrial cancer (n = 1). Patients were evaluated preoperatively with spiral CT scans and intraoperatively with ultrasound examinations for lesion location and cryoprobe guidance. Local recurrence was detected by CT. Major complications included bleeding in three patients and acute renal failure, transient liver insufficiency, and postoperative pneumonia in one patient each. Two patients (5%) died during the early postoperative interval; mean hospital stay was 7.1 days. Median follow-up was 28 months (range 18 to 51 months). Overall survival according to Kaplan-Meier analysis was 82%, 65%, and 54% at 12, 24, and 48 months, respectively. Forty-eight-month survival was not significantly different between those patients undergoing cryoablation alone (64%) and those treated with a combination of resection and cryoablation (42%). Disease-free survival at 45 months was 36% for patients undergoing cryoablation plus resection compared to 25% for those undergoing cryoablation alone. Local recurrences were detected at five cryosurgical sites, for a rate of 12% overall (5 of 42), 11% (2 of 18) for patients in the cryoablation plus resection group, and 12% (3 of 24) for those in the cryoablation alone group. For patients with colorectal metastases, survival was 70% at 30 months compared to 33% for hepatocellular cancer and 66% for other types of tumors. Patients with tumors larger than 5 cm or numbering more than three did not have significantly decreased survival. Cryoablation of hepatic tumors is a safe and effective treatment for some patients not amenable to resection. The combination of cryoablation and resection results in survival comparable to that achieved with cryoablation alone.

Adult↗
PubMedDate not supplied

Respective role of antibodies and immune macrophages during acquired immunity against toxoplasmosis in mice.

Immunity of animals correlated with the destructive ability of their macrophages. Intraperitoneal inoculation of T. gondii led to a very limited infection of macrophages from immune mice. This infection was next rapidly and completely inhibited. Conversely, macrophages from mice immunized with killed toxoplasma were massively invaded and evolved like control cells. Similar results were also obtained with macrophage cultures infected in vitro and followed over a period of 4 days. Even after several washes, immune macrophages still preserved their ability to inhibit intracellular replication of toxoplasma. However, this resistance was not homogenous: in the absence of antibodies, some macrophages supported a parasitic growth whereas some others remained intact. Results have also shown that the engulfment capability of immune macrophages was not modified. The primary role of resistant macrophages in the immune response did not however exclude a participation of humoral factors. Specific antibodies acted on extracellular toxoplasma either by lysing them in the presence of the accessory factor or by slowing their active penetration into the cells. Furthermore, they did not affect the phagocytic activity of macrophages. The in vitro protective role of peritoneal exudate from immune mice seemed similar to that afforded by sera anti-toxoplasma antibodies.

Animals↗